X-ray CT apparatuses, which provide information on an object by means of images based on the intensity of X-rays transmitted through the object, have been playing an important role in various medical practices, including diagnostics and treatments of diseases, and surgical planning.
In recent years, the X-ray CT apparatus utilizes a technique called Dual Energy Scan. The Dual Energy Scan is a technique to generate image data sets by performing an imaging using two different kinds of tube voltages.
As conventional reconstruction methods available when the Dual Energy Scan is used, two types of construction methods exist: dual energy reconstruction based on image data sets, and dual energy reconstruction based on projection data sets. The dual energy reconstruction based on the image data sets generates the image data sets from the projection data sets obtained at a high tube voltage and a low tube voltage respectively, and thereafter performs decomposition calculation on the image data sets to generate reference-material image data sets.
On the other hand, the dual energy reconstruction performs, in a non-helical scan, decomposition calculation respectively on a pair (Low-kV and High-kV) of actual measured projection data sets at same slice center position, and thereafter generates reference-material image data sets.
Thus, it is an objective of the present invention to provide an X-ray CT apparatus which enables high precision dual energy reconstruction based on the projection data sets.